Что не так со спецификацией драгоценных камней?

Я почти все сделал в этой инструкции, но получил ряд ошибок. Вот журнал:

stanley@ubuntu:~$ mkdir railstest
stanley@ubuntu:~$ rails new railstest
Invalid gemspec in [/var/lib/gems/1.8/specifications/mime-types-1.18.gemspec]: invalid date format in specification: "2012-03-21 00:00:00.000000000Z"
Invalid gemspec in [/var/lib/gems/1.8/specifications/tilt-1.3.3.gemspec]: invalid date format in specification: "2011-08-25 00:00:00.000000000Z"
Invalid gemspec in [/var/lib/gems/1.8/specifications/mail-2.4.4.gemspec]: invalid date format in specification: "2012-03-14 00:00:00.000000000Z"
       exist  
      create  README.rdoc
      create  Rakefile
      create  config.ru
      create  .gitignore
      create  Gemfile
      create  app
      create  app/assets/images/rails.png
      create  app/assets/javascripts/application.js
      create  app/assets/stylesheets/application.css
      create  app/controllers/application_controller.rb
      create  app/helpers/application_helper.rb
      create  app/mailers
      create  app/models
      create  app/views/layouts/application.html.erb
      create  app/mailers/.gitkeep
      create  app/models/.gitkeep
      create  config
      create  config/routes.rb
      create  config/application.rb
      create  config/environment.rb
      create  config/environments
      create  config/environments/development.rb
      create  config/environments/production.rb
      create  config/environments/test.rb
      create  config/initializers
      create  config/initializers/backtrace_silencers.rb
      create  config/initializers/inflections.rb
      create  config/initializers/mime_types.rb
      create  config/initializers/secret_token.rb
      create  config/initializers/session_store.rb
      create  config/initializers/wrap_parameters.rb
      create  config/locales
      create  config/locales/en.yml
      create  config/boot.rb
      create  config/database.yml
      create  db
      create  db/seeds.rb
      create  doc
      create  doc/README_FOR_APP
      create  lib
      create  lib/tasks
      create  lib/tasks/.gitkeep
      create  lib/assets
      create  lib/assets/.gitkeep
      create  log
      create  log/.gitkeep
      create  public
      create  public/404.html
      create  public/422.html
      create  public/500.html
      create  public/favicon.ico
      create  public/index.html
      create  public/robots.txt
      create  script
      create  script/rails
      create  test/fixtures
      create  test/fixtures/.gitkeep
      create  test/functional
      create  test/functional/.gitkeep
      create  test/integration
      create  test/integration/.gitkeep
      create  test/unit
      create  test/unit/.gitkeep
      create  test/performance/browsing_test.rb
      create  test/test_helper.rb
      create  tmp/cache
      create  tmp/cache/assets
      create  vendor/assets/javascripts
      create  vendor/assets/javascripts/.gitkeep
      create  vendor/assets/stylesheets
      create  vendor/assets/stylesheets/.gitkeep
      create  vendor/plugins
      create  vendor/plugins/.gitkeep
         run  bundle install
Invalid gemspec in [/var/lib/gems/1.8/specifications/mime-types-1.18.gemspec]: invalid date format in specification: "2012-03-21 00:00:00.000000000Z"
Invalid gemspec in [/var/lib/gems/1.8/specifications/tilt-1.3.3.gemspec]: invalid date format in specification: "2011-08-25 00:00:00.000000000Z"
Invalid gemspec in [/var/lib/gems/1.8/specifications/mail-2.4.4.gemspec]: invalid date format in specification: "2012-03-14 00:00:00.000000000Z"
Invalid gemspec in [/var/lib/gems/1.8/specifications/mime-types-1.18.gemspec]: invalid date format in specification: "2012-03-21 00:00:00.000000000Z"
Invalid gemspec in [/var/lib/gems/1.8/specifications/tilt-1.3.3.gemspec]: invalid date format in specification: "2011-08-25 00:00:00.000000000Z"
Invalid gemspec in [/var/lib/gems/1.8/specifications/mail-2.4.4.gemspec]: invalid date format in specification: "2012-03-14 00:00:00.000000000Z"
Invalid gemspec in [/var/lib/gems/1.8/specifications/mime-types-1.18.gemspec]: invalid date format in specification: "2012-03-21 00:00:00.000000000Z"
Invalid gemspec in [/var/lib/gems/1.8/specifications/tilt-1.3.3.gemspec]: invalid date format in specification: "2011-08-25 00:00:00.000000000Z"
Invalid gemspec in [/var/lib/gems/1.8/specifications/mail-2.4.4.gemspec]: invalid date format in specification: "2012-03-14 00:00:00.000000000Z"
Enter your password to install the bundled RubyGems to your system: 
Fetching gem metadata from https://rubygems.org/.........
Using rake (0.9.2.2) 
Using i18n (0.6.0) 
Using multi_json (1.3.5) 
Using activesupport (3.2.3) 
Using builder (3.0.0) 
Using activemodel (3.2.3) 
Using erubis (2.7.0) 
Using journey (1.0.3) 
Using rack (1.4.1) 
Using rack-cache (1.2) 
Using rack-test (0.6.1) 
Using hike (1.2.1) 
Installing tilt (1.3.3) 
Using sprockets (2.1.3) 
Using actionpack (3.2.3) 
Installing mime-types (1.18) 
Using polyglot (0.3.3) 
Using treetop (1.4.10) 
Installing mail (2.4.4) 
Using actionmailer (3.2.3) 
Using arel (3.0.2) 
Using tzinfo (0.3.33) 
Using activerecord (3.2.3) 
Using activeresource (3.2.3) 
Using bundler (1.1.3) 
Installing coffee-script-source (1.3.3) 
Installing execjs (1.3.2) 
Installing coffee-script (2.2.0) 
Using rack-ssl (1.3.2) 
Using json (1.7.3) 
Using rdoc (3.12) 
Using thor (0.14.6) 
Using railties (3.2.3) 
Installing coffee-rails (3.2.2) 
Installing jquery-rails (2.0.2) 
Using rails (3.2.3) 
Installing sass (3.1.18) 
Installing sass-rails (3.2.5) 
Installing sqlite3 (1.3.6) with native extensions 
Installing uglifier (1.2.4) 
Your bundle is complete! Use `bundle show [gemname]` to see where a bundled gem is installed.

Каково ваше впечатление о проблемах, которые вызывают эту проблему с gemspec?